Field of the Invention
The present invention relates to methods and apparatus for fixing dental components to dental implants in a patient's jawbone. More specifically, the invention relates to the manipulation of screws into dental components with corresponding screw channels in order to secure the dental component to the dental implant.
Description of the Related Art
FIG. 1 shows an arrangement for a prosthetic single tooth replacement having angulated screw channels. Dental implant 110 comprises screw channel 130 having an inner thread configured to match the thread of screw 160 such that screw 160 can be fastened to the implant. Prosthesis 120 is fixed to the dental implant by means of screw 160. The prosthesis passes through the gum tissue to dental implant 110. The prosthesis has a screw channel 190 through which screw 160 is inserted. Screw channel 190 has a screw channel exit 180 and screw seat 140 at the base of the prosthesis, upon which the head 170 of the screw 160 is seated when the prosthesis is fastened to the implant with the screw. According to the present invention, the axis of screw channel 190 (i.e. the line described by the radial centre point of the channel at any point) does not follow the axis of channel 130. In fact, screw channel 190 may be mostly straight but orientated at a different angle to channel 130. Alternatively, the axis of screw channel 190 may be curving or S-shaped. As a result, the axis of screw channel 190 at the channel exit 180 does not match the axis of channel 130 or the axis of screw seat 140.
The problem arising from this arrangement is that of how to insert the screw through the angulated screw channel and, once the screw is engaged with the dental implant, how to drive the screw to rotate using a driver angled at a significant angle from the longitudinal axis of the screw.
What is needed is a way of interfacing the screw and a driver tool in a manner which allows the screw to be manipulated during insertion into the prosthesis and driven to rotate from an angle to the longitudinal axis of the screw.
US 2010167240 describes a driver tool for driving a screw to rotate from an angle from the axis of the screw. A ball-headed driver is described, wherein the ball shape of the driver head apparently provides an interface between the driver and the screw, even where the driver tool is presented at an angle from the axis of the screw.